1. Technical Field
Embodiments of the present disclosure relate to signal processing, and more particularly to systems and devices and a method of crest factor reduction utilizing amplitude gain compression.
2. Description of Related Art
Modern communication systems use wideband transmission waveforms that contain multiple carriers and/or sub carriers. These transmission waveforms are not constant in amplitude, but can have very fast amplitude variations wherein the peak amplitude is substantially larger than the root mean square (rms) amplitude. The multi carrier signal is transmitted using a multi carrier power amplifier (MCPA) to transmit the signal at a very high efficiency, while maintaining acceptable signal quality and a high adjacent channel power ratio to meet the spectral emission mask requirements.
To maximize efficiency of a power amplifier (PA), it is desirable to transmit the signal near the saturation power levels PSAT. However, if the peak amplitude of the signal reaches PSAT then the signal will suffer distortion which may accumulate to cause high inter-modulation distortion. As the levels of inter-modulation distortion may be very high, the digital pre-distortion may fail to fully correct the amplitude distortion, and the inter-modulation (IMD) may be higher than that allowed by the required spectral emission mask.
To avoid this problem, the signal may be transmitted at lower levels to avoid the peak signal reaching PSAT. But this simple back-off approach results in lower PA efficiency, which is a key performance parameter.